Add a saved document library and in-app PDF reader

app/src/main/java/org/fairscan/app/FairScanApp.kt

@@ -26,6 +26,7 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.launch
 import org.fairscan.app.data.FileLogger
+import org.fairscan.app.data.DocumentLibrary
 import org.fairscan.app.data.FileManager
 import org.fairscan.app.data.LogRepository
 import org.fairscan.app.data.OcrLanguageRepository
@@ -57,6 +58,7 @@ class AppContainer(context: Context) {
     private val cacheDir = context.cacheDir
     private val dataStore = context.dataStore
     val preparationDir = File(context.cacheDir, "pdfs")
+    val documentLibrary = DocumentLibrary(context.applicationContext)
     val ocrLanguageRepository =
         OcrLanguageRepository(dataStore, File(context.filesDir, "tesseract/tessdata"))
     val ocrService = OcrService(ocrLanguageRepository, scope)

app/src/main/java/org/fairscan/app/MainViewModel.kt

@@ -54,7 +54,11 @@ import org.fairscan.imageprocessing.Quad
 import kotlin.math.min
 
 @OptIn(ExperimentalCoroutinesApi::class)
-class MainViewModel(val imageRepository: ImageRepository, logger: Logger): ViewModel() {
+class MainViewModel(
+    val imageRepository: ImageRepository,
+    logger: Logger,
+    private val launchMode: LaunchMode = LaunchMode.NORMAL,
+): ViewModel() {
 
     private val _navigationState = MutableStateFlow<NavigationState?>(null)
     val currentScreen: StateFlow<Screen?> = _navigationState.map { it?.current }
@@ -69,12 +73,9 @@ class MainViewModel(val imageRepository: ImageRepository, logger: Logger): ViewM
 
             _pages.value = pages
 
-            _navigationState.value =
-                if (pages.isEmpty()) {
-                    NavigationState.initial()
-                } else {
-                    NavigationState.initial().navigateTo(Screen.Main.ResumeScan)
-                }
+            _navigationState.value = NavigationState.initial(
+                externalScan = launchMode == LaunchMode.EXTERNAL_SCAN_TO_PDF
+            )
         }
     }
 
@@ -142,6 +143,10 @@ class MainViewModel(val imageRepository: ImageRepository, logger: Logger): ViewM
         _navigationState.update { stack -> stack?.navigateBack() }
     }
 
+    fun openScanner() {
+        navigateTo(if (_pages.value.isEmpty()) Screen.Main.Camera else Screen.Main.ResumeScan)
+    }
+
     fun rotateCurrentPage(clockwise: Boolean) {
         viewModelScope.launch {
             val pages = withContext(Dispatchers.IO) {
@@ -217,12 +222,14 @@ class MainViewModel(val imageRepository: ImageRepository, logger: Logger): ViewM
             "No current page for index $index (${pages.size} pages)")
     }
 
-    fun startNewDocument() {
+    fun startNewDocument(onCleared: () -> Unit = {}) {
         _pages.value = persistentListOf()
         viewModelScope.launch {
             withContext(Dispatchers.IO) {
                 imageRepository.clear()
             }
+            _currentPageIndex.value = 0
+            onCleared()
         }
     }
 

app/src/main/java/org/fairscan/app/data/DocumentFilenames.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2025-2026 The FairScan authors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.fairscan.app.data
+
+import java.io.File
+
+fun safeDocumentName(name: String): String {
+    val cleaned = name.trim()
+        .replace(Regex("[\\\\/:*?\"<>|\\p{Cntrl}]"), "_")
+        .trim('.', ' ')
+        .ifBlank { "FairScan" }
+    val extension = cleaned.substringAfterLast('.', "")
+        .takeIf { it.lowercase() in setOf("pdf", "jpg", "jpeg") }
+        ?.let { ".$it" }.orEmpty()
+    var base = cleaned.removeSuffix(extension)
+    // Android filesystems limit names in bytes; leave room for an extension and collision suffix.
+    while (base.toByteArray(Charsets.UTF_8).size > 180) {
+        base = base.substring(0, base.offsetByCodePoints(base.length, -1))
+    }
+    return base.ifBlank { "FairScan" } + extension
+}
+
+fun availableDocumentFile(directory: File, filename: String): File {
+    val desired = File(directory, safeDocumentName(filename))
+    var target = desired
+    var suffix = 1
+    while (target.exists()) {
+        target = File(directory, "${desired.nameWithoutExtension} ($suffix).${desired.extension}")
+        suffix++
+    }
+    return target
+}